For server-based e-mail, it is recommended that you use SMTP mail rather than POP3. There are several third-party products available (for example: http://www.popbeamer.com) you can configure to download e-mail more often, but the SBS POP3 connector cannot be adjusted below 15 minutes.

To set up an SMTP mail account with your ISP, have them point the MX (Mail Exchanger) records to your static IP address.

If you have dynamic IP address, explore the options for dynamic DNS software, such as those at http://www.tzo.com.